A)Two larger music stores that buy and sell used CDs around here have a polishing machine they run all their used buyouts through before putting in store inventory.And for about a dollar per they will run discs I bring through that polisher(looks like new again).I have had several done with great results.Call around the larger independents in your area and ask them about CD polishing service.
B)There is a product called CDfender,made to apply on data side,like a clear-bra for an automobile,it sticks onto the data side to protect from scratches,can be removed and according to the FAQ page see below:
Q. Will CDfender repair damaged CD's, mend scratches and prevent skipping?
A. The special optical couplant on the CDfender fills in minor scratches on the surface of the CD and repairs them.
They sell for $11.00 per ten/pack.
I have not tried this product but check out their site
CDfender